As the circuit density of microelectronic components increases, heat generated by these devices may typically increase as well. Microelectronic components may include, for example, microprocessors, such as central processing units (CPU), graphic processing units (GPU), digital signal processors (DSP); one or more memory devices; one or more application specific integrated circuits (ASIC); and/or other types of electronic components such as capacitors and/or resistors, as just a few examples. Microelectronic components may include an integrated circuit located within a bath-tub recess in a package. Such integrated circuits may be thermally and mechanically coupled to the package on one side, such as by a gold eutectic compound, for example. The reverse side of the integrated circuit may be temporarily left open. Pads may be placed around the edge of the integrated circuit and tiny bonding wires may be attached from the pads to the package. After bonding is complete, a cap may typically be placed over the opening of the bath tub in order to protect the bonding wires.
Various techniques may typically be used to remove or dissipate heat generated by a microelectronic component. These techniques may include passive and/or active thermal solutions, for example. One such technique, which may be classified as a passive thermal solution, may involve the use of a thermally conductive device in thermal contact with a microelectronic component. This thermally conductive device may comprise a mass of thermally conductive material such as a slug or heat spreader, or may comprise a device configured to enhance convective heat transfer, such as a heat sink. However, techniques for heat dissipation and/or removal may not produce the desired results, and additional techniques and/or devices for dissipating and/or removing heat may be used.
For example, a heat sink may be bonded to an integrated circuit package. This may typically be done by a systems manufacturer who bought the packaged integrated circuit from an integrated circuit vendor. Though, the integrated circuit vendors may sell packaged integrated circuits with heat sinks already attached. The heat sink may be bolted or bonded to the package, and heat transfer compound may be placed on the integrated circuit and/or heat sink before the bonding in order to facilitate the thermal conductivity between the integrated circuit and the heat sink. Sometimes, the package body itself may be expected to radiate sufficient heat, and a separate heat sink may not be included. Typically, the heat flow through a heat sink may be a function of f(Tbonded−Topen) where Topen is the temperature of open side of the heat sink, and Tbonded is the temperature at the bonded side. As Topen decreases, heat flow significantly increases, and thus Tbonded may also decrease. For this reason some manufacturers may place fans directly on the heat sink to cause Topen, to drop near Tambient, the ambient temperature of the assembly.
The whole assembly of a heat sink and an integrated circuit package may then be placed on a system board. By definition, the entity that places the assembly on the system board is the systems manufacturer. It is not unheard of for integrated circuit vendors to also be systems manufacturers. In some systems, there may be multiple integrated circuits on the board, with the possibility of daughter boards. One or more of the integrated circuits may have heat sinks. Once the assembly has been placed on the system board, the system board may then in turn be placed in an enclosure. The enclosure may trap heat, causing Tambient to rise, and then consequently causing Topen to rise, and then Tbonded to rise. If the Tbonded rises too far, the integrated circuit may melt and be destroyed. In order to lower Tambient within the enclosure, some manufacturers may place fans on the enclosure. This may cause Tambient to drop towards Troom, the temperature in the room where the enclosed computer is being used.
Reference is made in the following detailed description to the accompanying drawings, which form a part hereof, wherein like numerals may designate like parts throughout to indicate corresponding or analogous elements. It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, it is to be understood that other embodiments may be utilized and structural and/or logical changes may be made without departing from the scope of claimed subject matter. It should also be noted that directions and references, for example, up, down, top, bottom, and so on, may be used to facilitate the discussion of the drawings and are not intended to restrict the application of claimed subject matter. Therefore, the following detailed description is not to be taken in a limiting sense and the scope of claimed subject matter defined by the appended claims and their equivalents.